1. FIELD OF THE INVENTION
The present invention relates generally to stator constructions for dynamo-electric machines, and more particularly to a laminated stator comprised of a stack of plate laminations, wherein each of the laminations has a number of teeth extending radially from an inner bore opening, the teeth including lip parts to retain a stator winding with a closure wedge embedded in slots formed between adjacent teeth.
2. DESCRIPTION OF THE KNOWN ART
Laminated stators for dynamo-electric machines are known generally from, for example, U.S. Pat. No. 3,469,136 (Sept. 23, 1969). Basically, the machine stator is comprised of a number of annular plate laminations of ferromagnetic material, stacked face-to-face with one another. Each plate has a circular inner opening to form a stator bore when the plates are stacked, and a number of equally circumferentially spaced slot openings extending radially from the circumference of the inner opening to form a number of teeth between which one or more stator windings are to be embedded.
When the plate laminations are stacked in proper alignment to form the stator, the winding slots in each plate together form a number of stator winding slots or recesses which extend generally parallel to the axis of the stator bore and a certain depth radially outward from the bore. One or more stator windings are then wound through selected ones of the slots between adjacent teeth, according to the number of poles desired for the machine. Prior to inserting the winding conductors, a slot insulator or liner is usually inserted to extend axially along each slot in contact with the lamination material, to prevent arcing or short-circuiting between the winding conductors and the ferromagnetic material, of which the laminations are made.
Each winding conductor is then inserted through mouth openings formed between adjacent teeth to enter the slot and, when all conductors of the winding or windings associated with the slot are in place, a closure wedge is inserted into the mouth slot, and lip parts of adjacent teeth which project into the mouth of the slot retain the wedge in place. See, for example, U.S. Pat. No. 4,486,506 (Dec. 4, 1984). Until now, it has been the practice to incline the edge of each lip part which edge faces the closure wedge, at an angle of 22.5 degrees relative to a line perpendicular to the slot center line. It has been found, however, that for a given mouth opening between confronting lip parts of adjacent teeth, the 22.5 degree inclination angle may not be sufficient to seat the closure wedges firmly in place with the result that the wedge and possibly some of the winding conductors protrude from the slot mouth and contact the machine rotor with damaging results.